In some processes, such as epitaxial deposition of a layer on a substrate, process gases may be flowed across a substrate surface in the same direction. For example, the one or more process gases may be flowed across a substrate surface between an inlet port and an exhaust port disposed on opposing ends of a process chamber to grow an epitaxial layer atop the substrate surface.
Typically, conventional wisdom is that temperature is by far the predominant variable for controlling film thickness. As such, temperature control of the substrate and/or of the process environment is utilized to attempt to control film thickness deposited on the substrate.
The inventors have provided herein improved methods and apparatus for processing substrates.